This is the problem with older systems that there is not much choice to change the existing RS232 at the machine.
There is not a great deal of cost involved in trying a USB or ethernet convertor, the s/w you get with the convertor usually sets it up as a standard serial port so the software doesn't know the difference (hopefully)!.
The other alternative is to see what Cadem now has to offer in the way of other interfaces for DNC.
Your older machine also has to be DNC compatible though.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.